In recent years phototherapy continues to be one of the essential therapeutic treatment options for patients with mild to moderate psoriasis, either as a monotherapy or in combination with other standard treatment modalities, such as systemic and topical agents.
There are two types of phototherapy for psoriasis, UVA and UVB and both have shown good response in treating psoriasis. UVB have shown to be more effective then UVB for treating psoriasis.
UVB Therapy
High dose UVB therapy is as effective as PUVA in treating patients with psoriasis and it can be used during pregnancy and lactation or in patients with hepatic or renal failure. There are two types of UVB therapy: Broadband UVB and Narrowband UVB. UVB treatment can be given on daily basis or 3-5 times a week until the lesion is cleared. Recently Narrowband UVB is being widely used as it has more advantage over Broadband UVB as it can be used in any patients including children and pregnant women.
UVA Therapy
UVA therapy penetrates deep into the skin than with UVB therapy. For UVA to be effective combination of UVA with photosensitizing medication like psoralen( PUVA) is used. Treatment is usually given 2-4 times a week until lesion clears. As PUVA make the skin more sensitive to light, one should avoid sun as much a possible.
Side Effect of Phototherapy in psoriasis
Short-term side effects:
Erythema (sunburn)
Dry skin with pruritus
Swelling
Phototoxic blisters
The frequency of recurrent herpes simplex might increase.
Long-term side effects of UV therapy include
Photo aging
Increase risk of skin cancer
Pigmentary changes
Xerosis
Loss of elasticity
Wrinkle formation
Actinic keratoses.
Hypertrichosis
Dark lentigines (“PUVA lentiginosis”).
If the treatment involves phototherapy (short-term exposure to B type UV, known as UVB), the exposure to ultraviolet (UVB phototherapy) is frequently used in the treatment psoriasis and has good results in relieving the symptoms of skin.
Innovative and inexpensive light boxes are coming out that can be used in the home for personal phototherapy. Most of these light boxes do not yet produce UV but rather infrared light, which is of large wavelength and not likely to burn the patient. UV light boxes must be handled more carefully, since there is the risk of overexposure to the light and resulting sunburn.